Recently, as shown in FIG. 6(a), a method for producing a pneumatic tire where an unvulcanized ribbon-like rubber strip (a) is wound on an outer surface of a rigid core to form a green tire has been proposed. The rigid core has a shape similar an inner cavity of the pneumatic tire to be manufactured. In order to extrude the rubber strip (a), a rubber extrusion device (b) as shown in FIG. 6(b) has been proposed.
The rubber extrusion device (b) includes a rubber extruder (c) and a gear pump (d), for instance. The rubber extruder (c) is configured to have a screw shaft for kneading unvulcanized rubber and ext riling the same. The gear pump (d) is configured to include a gear pump main body (h) that comprises an electric motor (f), a reduce (g) linked to the electric motor (f), and a pair of gears. The gear pump (d) receives extruded rubber from the rubber extruder and then may quantitatively discharge it. The gear pump (d) includes an outlet port (e) for discharging a preliminary rubber strip. To form rubber strip (b), the preliminary rubber strip may further be pressed between a pair of calendar rolls.
Unfortunately, since the conventional rubber extrusion device (b) includes three parallel axes, i.e. a rotating shaft of the electric motor (f), an output shaft of the reducer (g), and rotating axes of gears, the electric motor (f) and the reducer (g) have to be arranged laterally outside the gear pump rain body (h). Thus, to install the rubber extrusion device on the floor, a large plane space is necessary. In particular, as shown in FIG. 7, when two rubber extrusion devices (b) are arranged in parallel one another, there is a problem that further larger space is necessary. The relevant a prior arts are as follows.